1. Field of this Invention
The present invention relates to a centrifugal separation-use device for collecting a target component from a liquid, such as blood, containing multiple components by centrifugal separation treatment while its inner container is maintained in a sterilized state.
2. Description of the Prior Art
The blood subjected to centrifugal separation treatment after addition of an anticoagulant is largely separated into three layers, a red blood cell layer, a white blood cell layer and a plasma layer. Since the components contained in the respective separated layers are very useful for living tissue, they are used for various medical treatment methods.
It is known that the platelets contained in the plasma layer release various cytokines including platelet-derived growth factor (PDGF) due to degranulation in the process of a blood coagulation reaction. For this reason, it is attempted to use plasma (platelet-rich plasma: PRP) containing platelets in high concentrations for regenerative medicines (for example, refer to Patent Document 1).
Various methods have been examined as methods for collecting PRP. Specifically speaking, first, primary centrifugal separation treatment with relatively weak centrifugal force is carried out for collected blood. After the centrifugal separation treatment, the red blood cells are localized on the centrifugal side of the rotation and the plasma is present on the center side of the rotation due to the difference in specific gravity of the components. At the boundary between them, plasma containing white blood cells and platelets are present. The plasma corresponding to the supernatant fluid portion, containing the layer of platelets, is transferred to another centrifugal separation-use container. Next, secondary centrifugal separation treatment with relatively strong centrifugal force is carried out to separate the plasma into a PRP layer and a plasma (platelet-poor plasma: PPP) layer containing platelets in low concentrations. Then, the PPP layer corresponding to the supernatant fluid portion is removed to collect the PRP layer. This method in which centrifugal separation treatment is carried out twice is used frequently since the state after the centrifugal separation treatment is satisfactory. Hence, methods for easily collecting PRP using this collection method have been examined variously (for example, refer to Patent Documents 2 and 3).
Furthermore, cells can be fractionated depending on target cell type by subjecting bone marrow fluid and cord blood containing stem cells to centrifugal separation treatment instead of using blood as the liquid to be subjected to centrifugal separation treatment. This method is also used as a regenerative medicine.
[Patent Document 1]
    Japanese Patent Application Laid-Open Publication No. 2006-122518[Patent Document 2]    Japanese Patent Application Laid-Open Publication No. Hei 09-103707[Patent Document 3]    Japanese Patent Application Laid-Open Publication No. 2006-78428
Various devices have been examined to see if each component is easily subjected to centrifugal separation treatment on the assumption that the devices are sterilized and that the components having been subjected to centrifugal separation treatment are used for medical treatment as a matter of course. However, when an attempt is made to carry out collection using the above-mentioned method, all the devices are required to be used while being set in a centrifugal separator. Hence, when they are set in the rotor of a centrifugal separator that is not sterilized, their outside-air sides become unclean. Since an operator is required to be kept clean in any operation from the beginning to the end of the operation, an assistant in an unclean field, other than the operator, is required when a collected component is used. Hence, the assistant in the unclean field and the outside-air side of the device in the unclean field become close to the affected area of a patient and may increase the risk of infection in an operation in which a material is embedded. For this reason, there occurs a circumstance in which the use of centrifugal separation treatment is avoided depending on the type of operation.
For the purpose of carrying out centrifugal separation treatment under such a circumstance, the outside-air side of the device is required to be kept clean. As a method for keeping the outside-air side clean, it is conceivable to use a method in which a sterilized bag formed of rolled paper or the like is used. However, since the sterilized bag is insufficient in strength, there is a problem of having a high risk that the sterilized bag is torn when centrifugal separation treatment is carried out. Furthermore, although it is also conceivable to use a method for sterilizing the rotor of a centrifugal separator, there is a problem of imposing quite a burden when the rotor of a large-size centrifugal separator is sterilized for each operation. Moreover, although it is further conceivable to use a method for automatically carrying out centrifugal separation treatment under a sterile environment using an automated centrifugal separator or the like, there is a problem of the very high cost of the centrifugal separator.